ACCUMULATION OF GUANOSINE TETRAPHOSPHATE (PPGPP) UNDER NITROGEN STARVATION IN ANACYSTIS-NIDULANS, A CYANOBACTERIUM
ACCUMULATION OF GUANOSINE TETRAPHOSPHATE (PPGPP) UNDER NITROGEN STARVATION IN ANACYSTIS-NIDULANS, A CYANOBACTERIUM
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DOI：
10.1007/bf00406458
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发表时间：
1981-01-01
影响因子：
2.8
通讯作者：
FARKAS, GL
中科院分区：
文献类型：
--
作者：
FRIGA, GM;BORBELY, G;FARKAS, GL
研究了硝酸盐剥夺对多核拟青霉细胞生长和核苷酸水平的影响。硝酸盐水平降低10倍，导致增长急剧放缓。在饥饿的培养物中加入硝酸盐后，经过一段时间后，细胞恢复生长。营养水平的降低导致鸟苷四磷酸(PpGpp)池的一过性扩张，随后是GTP和ATP浓度的一过性增加。在达到峰值后，ppGpp、GTP和ATP的浓度下降到各自的基线水平。PpGpp池的扩大是由于ppGpp合成的增加，而不是ppGpp分解的减少。营养调升后，ppGpp水平未见下降。在饥饿的细胞中，观察到游离氨基酸的减少伴随着ppGpp池的扩大。游离氨基酸水平开始与ppGpp池的收缩同步增加。
The effect of nitrate deprivation on cell growth and nucleotide level was studied in A. nidulans. A 10-fold reduction in nitrate level resulted in a drastic slowdown of growth. Upon addition of nitrate to the starving cultures, after a lag period, the cells resumed growth. Nutritional shift-down induced a transitory expansion of the guanosine tetraphosphate (ppGpp) pool, preceeded by a transitory increase in GTP and ATP concentrations. After having reached peak values, the concentration of ppGpp, GTP and ATP dropped to the respective base levels. The expansion of the ppGpp pool was due to an increase in ppGpp synthesis, rather than to a decrease in ppGpp breakdown. After nutritional shift-up, there was no decrease in the ppGpp level. In starving cells, a decrease in free amino acids was observed to occur concomitantly with the expansion of the ppGpp pool. The level of free amino acids started to increase simultaneously with the contraction of the ppGpp pool.